The StreamReaderWriter allows wrapping streams which work in
both read and write modes.
The design is such that one can use the factory functions returned by
the lookup() function to construct the instance.
classStreamReaderWriter(
stream, Reader, Writer, errors)
Creates a StreamReaderWriter instance.
stream must be a file-like object.
Reader and Writer must be factory functions or classes
providing the StreamReader and StreamWriter interface
resp.
Error handling is done in the same way as defined for the
stream readers and writers.
StreamReaderWriter instances define the combined interfaces of
StreamReader and StreamWriter classes. They inherit
all other methods and attributes from the underlying stream.
